Relay apparatus



June 18, 1968 o. A. WALES 3,389,310

RELAY APPARATUS Filed Feb. 7, 1966 FIG. 1

L INVENTOR. Dom/11.0 A. WALES BY F154 4 Wfiumd ATTORNEY) United States Patent 3,389,310 RELAY APPARATUS Donald A. Wales, Minneapolis, Minn., assignor to Flo- Tronics, Incorporated, Minneapolis, Minn., a corporation of Minnesota Filed Feb. 7, 1966, Ser. No. 525,757 Claims. (Cl. 317-123) This invention is concerned with electromagnetic control apparatus, and more particularly with an improved electromagnetic relay, powered from a source of alternating energy.

This invention provides many advantages in a well known art. The apparatus of this invention provides a fail-safe relay, having high traction which is at the same time steady and quiet, at a low energy input. The apparatus also eliminates high initial current inrush, and has a low temperature rise. Further, the novel apparatus is designed to be inexpensively and easily produced.

Briefly described, the apparatus of this invention com- ,prises a magnetic core member having at least three legs.

A first and a second of the legs are connected in a closed magnetic circuit, while a third of the legs is connected in series with an air gap across the second leg. A tractive type armature is provided adjacent the air gap. Alternating power is provided to the winding around the first leg to cause an alternating magnetic flux flow in the core member. Normally, the alternating flux will flow in the closed magnetic loop comprising the first and second legs. A second winding around the second leg has connected across it a rectifier. The rectifier is poled to inhibit flux flow through the second leg in one direction, with the result that on alternate half-cycles, the magnetic flux takes the preferred path through the third leg and the air gap, thus providing a unidirectional flux flow through the air gap. In the presence of this unidirectional flux flow, the armature is attracted to the magnetic core member. There is also provided a third winding around the third leg which has connected across it another rectifier. This latter rectifier is so poled to inhibit the collapse of the magnetic field around the third winding in the alternate half-cycles of magnetic flux which do not how through the third leg. Thus the magnetic field around the third winding tends to continue the unidirectional flux flow through the air gap during alternate half-cycles when flux is not provided from the actuating circuit.

In the drawings:

FIGURE 1 is a schematic representation of an embodiment of the apparatus of this invention;

FIGURE 2 is a schematic representation of a variation of the embodiment of FIGURE 1;

FIGURE 3 is a graph of a sine wave representing the alternating magnetic flux flow in the magnetic core member of the embodiments of FIGURES 1 and 2; and

FIGURE 4 is a schematic drawing of a modification of the wiring of the embodiment of FIGURE 2.

Referring first to FIGURE 1, there is shown a magnetic core member indicated generally at 10. Included in core member 10 are three legs 11, 12, and 13. Legs 11 and 12 arein a closed magnetic circuit loop within core member 10, while leg 13 is in series with an air gap 14 across leg 12. An armature 16, of the tractive type, is shown mounted adjacent air gap 14.

There is also shown a winding 21 around leg 11, a winding 22 around leg 12, and a winding 23 around leg 13. Winding 21 is connected across a source of alternating energy 18. Serially connected across winding 22 are a rectifying member 25 and a switch member 26. Connected across winding 23 is a rectifying member 27.

Referring now to FIGURE 2, there are shown the same components, indicated by the same numerals, as in FIG- 3,389,310 Patented June 18, 1968 "ice URE 1 with a modification in the wiring. Again, magnetic core member 10 is shown having legs 11, 12, and 13, leg 13 being in series with air gap 14 across leg 12. Winding. 21, around leg 11, is again connected to source 18. Armature 16 is again mounted adjacent air gap 14. Wind. ings 22 and 23 are again around, respectively, legs 12 and 13.

In FIGURE 2, winding 23 is connected across a pair of terminals 28 and 29. Rectifying member 27 is connected between terminals 28 and 29. One end of winding 22 is also connected to terminal 28. Rectifying member 25 and switch member 26 are serially connected between terminal 29 and the other end of winding 22.

In FIGURE 3 there is shown a sine wave 30 representing the alternating magnetic flux flow in magnetic core member 10. The unshaded half-cycles, such as 31, herein represent the first alternate half-cycles, while the shaded half-cycles, such as 32, herein represent the second alternate half-cycles.

In FIGURE 4 there is shown a modification of a portion of the wiring of the embodiment of FIGURE 2. Again there is shown windings 22 and 23, each being connected at a lower end to terminal 28. The upper end of winding 23 is again connected to terminal 29, and rectifying member 27 is connected between terminals 28 and 29. In this variation, the upper end of winding 22 is connected to a terminal 34. Rectifying member 25 and switch member 26 are serially connected between terminals 28 and 34. A conductor is connected between terminal 34 and a remote control station 37, indicated in dotted lines. A' conductor 36 is connected from terminal 28 to remote control station 37. Within station 37, a switch member 38 is connected between conductors 35 and 36. Also within station 37, a switch member 39 and a rectifying member 40 are connected in series between conductors 35 and 36.

The operation of the apparatus of this invention is best described by first referring to FIGURES 1 and 3. Source 18 provides an alternating current flow in winding 21, which in turn causes an alternating magnetic flux flow in core member 10, as represented by sine wave 30. Assuming switch member 26 is in its open position, as shown in FIGURE 1, the alternating magnetic flux will flow in the closed magnetic circuit loop including legs 11 and 12. No substantial magnetic flux will flow through leg 13 due to the low permeance of air gap 14 relative to core member 10. It will be assumed that during the first alternate half-cycles of flux 31, represented by the unshaded half-cycles of FIGURE 3, the flux flows counterclockwise from the bottom of leg 11, through leg 12, and back to the top of and through leg 11. During the second alternate half-cycles of flux 32, represented by the shaded half-cycles of FIGURE 3, the flux flows clockwise from the top of the leg 11, through leg 12, and back to the bottom of and through leg 11.

When switch member 26 is closed, rectifying member 25, here represented by a diode, is included in circuit across winding 22. This causes leg 12 to have a low permeance with respect to magnetic flux attempting to flow in the counterclockwise direction. Therefore, during the first alternate half-cycles of magnetic flux 31, the flux will be inhibited from flowing through leg 12 and will now flow from the bottom of leg 11, through leg 13 and air gap 14, and back to the top of and through leg 11. The resulting unidirectional flux in air gap 14 will cause armature 16, normally yieldingly biased away from air gap 14, to be attracted by the magnetic poles at each end of air gap 14.

During the second alternate half-cycles of flux 32, the flux flows freely clockwise through leg 12, as described above. This would cause a tendency for dropout of armature 16, which tendency is overcome by the use of winding 23 which has across it rectifying member 27, here shown as a diode. Rectifying member 27 is poled to prevent the decay of the magnetic field around winding 23, caused originally by the unidirectional fiux fiow through leg 13 during the first alternate half-cycles 31. Therefore, during the second alternate half-cycles 32, the collapse of the magnitude field tends to continue the unidirectional flux flow through Winding 13. Since this collapse or decay of the magnetic field is inhibited by rectifying member 27, the effect is to continue a significant unidirectional flux fiow through air gap 14 during the second alternate half-cycles.

Referring now to FIGURE 2, the operation of the circuit is substantially as described above, with the exception that the effect of the circuit of winding 23 and rectifying member 27 is enhanced by the wiring modification. Note that now winding 23 is in series with rectifying member 25 and switch member 26 across winding 22. Now, when switch member 26 is closed, winding 22 while inhibiting flux flow through leg 12 during the first alternate half-cycles 31, is at the same time providing an additional current flow through winding 23, which in turn strengthens the magnetic field around 23, to aid in the continuance of unidirectional flux flow through leg 13 during the second alternate half-cycles 32. Rectifying member 25 serves to prevent any significant effect on winding 23 of the clockwise flow of flux through leg 12, during the second alternate half-cycles of flux 32.

Reference to FIGURE 4 discloses a wiring modification which achieves another useful function of the relay apparatus of this invention. In this embodiment, switch members 38 and 39 in remote control station 37 can be momentary contact type switch members (or electronic or electromagnetic switches), while switch member 26 can be a normally opened contact controlled by movement of armature 16. Conductors and 36 connect the apparatus in control station 37 across winding 22. Again, the operation of this modified circuit is essentially as that described above. However, one may initiate armature pullin at remote control station 37 by closing switch member 39, which will place rectifying member across winding 22. This will initiate the flow of unidirectional flux through air gap 14 and armature 16 will pull in, as described above. When armature 16 pulls in, switch member 26 will close to hold the relay in the actuated condition. Thus the relay is self-latching. By closing member 38 in station 37, winding 22 is completely shorted out, causing armature 16 to be released, thus opening switch member 26 and breaking the relay latch.

It is important to note that the particular configuration shown for magnetic core member 10 is that of the preferred embodiment, and that several variations of this form will be apparent to those skilled in the art, without departing from the spirit of the invention. Further, mag netic member 10 may comprise any one of a number of different high permeance materials, such materials and their structure being well known to those skilled in the art.

It should also be noted that the number of turns in each of windings 21, 22 and 23 will vary depending on the particular specifications and characteristics of the relay apparatus desired. The turns shown in the windings of FIGURES 1 and 2 are merely intended to visually represent the windings and not necessarily a preferred ratio of turns between the windings.

It is intended that switch member 26 as shown in the embodiments of FIGURES 1 and 2, be manually or automatically controlled. For example, switch member 26 can comprise a semiconductor or other type of switching circuit, such as a logic circuit. Further, it is not intended that rectifying members 25, 27 and 40 be limited to diodes. Many kinds of well known rectifiers can replace the diodes shown in the preferred embodiments.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Relay apparatus comprising:

magnetic core means including first, second and third legs, and an air gap, said second leg connected across said first leg, said third leg and said air gap connected in series across said second leg;

first winding means wound around said first leg;

second winding means wound around said second leg;

third winding means wound around said third leg;

means including a source of alternating energy connected across said first winding means, for providing an alternating magnetic flux in said magnetic core means;

further means including first rectifying means connected across said second winding means, for inhibiting the flow of magnetic fiux through said second leg in a first direction to provide unidirectional magnetic flux fiow through said third leg and said air gap during first alternate half-cycles of said alternating magnetic flux;

still further means including second rectifying means connected across said third winding means, for inhibiting decay of the magnetic field of said third winding means during second alternate half-cycles of said alternating magnetic flux; and

armature means of the tractive type mounted adjacent said air gap and adapted to be attracted to said magnetic core means in the presence of unidirectional flux flow through said air gap.

2. The apparatus of claim 1 in which said further means includes switch means for selectively connecting said first rectifying means in and out of circuit with said second winding means.

3. The apparatus of claim 1 in which said further means including first rectifying means comprises said third winding means in series with said first rectifying means.

4. The apparatus of claim 3 in which said further means includes switch means for selectively connecting said first rectifying means and said third winding means in and out of circuit with said second winding means.

5. Relay apparatus comprsing:

magnetic core means including a plurality of legs;

a first winding around a first of said legs, said first winding connected to a source of alternating energy for inducing alternating magnetic flux in said core means;

at least a second winding around at least a second of said legs, said second leg being in closed magnetic circuit with said first leg;

at least first rectifying means connected across said second winding and poled to inhibit magnetic flux flow through said second leg in one direction;

at least a third leg separated from said second leg by an air gap, to provide a path for magnetic flux flowing in said one direction;

at least a third winding around said third leg;

at least a third rectifying means connected across said third winding and poled to inhibit the collapse of the magnetic field induced about said third winding by the magnetic flux flowing in one direction; and armature means mounted adjacent said air gap for attraction by magnetic flux flowing therethrough. 6. The apparatus of claim 5 including switch means in circuit with said first rectifying means for switching said first rectifying means in and out of circuit with said second Winding.

7. The apparatus of claim 5 in which said third winding and said first rectifying means are connected in series across said second winding.

8. The apparatus of claim 7 including switch means in circuit with said third winding and said first rectifying means.

9. Magnetic apparatus comprising:

a closed magnetic circuit loop including first and second parallel connected legs;

a second magnetic circuit loop including a third leg and an air gap serially connected across said second leg;

means connected to said first leg for providing alternating magnetic flux flow through said closed magnetic circuit loop;

means connected to said second leg for inhibiting flux flow through said second leg during first alternate half-cycles of said alternating flux flow;

means connected to said third leg and operative during second alternate half-cycles of said alternating flux flow to inhibit decay of flux flow through said third leg; and

nected to said second leg includes at least a portion of said means connected to said third leg.

References Cited UNITED STATES PATENTS 2,046,748 7/1936 Hudson 3l7l56 LEE T. HIX, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,389 ,3l 0 June 18 1968 Donald A. Wales It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

line 8, "magnitude" should read magnetic Column 3,

Column 4 line line 47, after "closing" insert switch 43, "comprsing" should read comprising Signed and sealed this 25th day of November 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Attesting Officer 

1. RELAY APPARATUS COMPRISING: MAGNETIC CORE MEANS INCLUDING FIRST, SECOND AND THIRD LEGS, AND AN AIR GAP, SAID SECOND LEG CONNECTED ACROSS SAID FIRST LEG, SAID THIRD LEG AND SAID AIR GAP CONNECTED IN SERIES ACROSS SAID SECOND LEG; FIRST WINDING MEANS WOUND AROUND SAID FIRST LEG; SECOND WINDING MEANS WOUND AROUND SAID SECOND LEG; THIRD WINDING MEANS WOUND AROUND SAID THIRD LEG; MEANS INCLUDING A SOURCE OF ALTERNATING ENERGY CONNECTED ACROSS SAID FIRST WINDING MEANS, FOR PROVIDING AN ALTERNATING MAGNETIC FLUX IN SAID MAGNETIC CORE MEANS; FURTHER MEANS INCLUDING FIRST RECTIFYING MEANS CONNECTED ACROSS SAID SECOND WINDING MEANS, FOR INHIBITING THE FLOW OF MAGNETIC FLUX THROUGH SAID SECOND LEG IN A FIRST DIRECTION TO PROVIDE UNIDIRECTIONAL MAGNETIC FLUX FLOW THROUGH SAID THIRD LEG AND SAID AIR GAP DURING FIRST ALTERNATE HALF-CYCLES OF SAID ALTERNATING MAGNETIC FLUX; STILL FURTHER MEANS INCLUDING SECOND RECTIFYING MEANS CONNECTED ACROSS SAID THIRD WINDING MEANS, FOR INHIBITING DECAY OF THE MAGNETIC FIELD OF SAID THIRD WINDING MEANS DURING SECOND ALTERNATE HALF-CYCLES OF SAID ALTERNATING MAGNETIC FLUX; AND ARMATURE MEANS OF THE TRACTIVE TYPE MOUNTED ADJACENT SAID AIR GAP AND ADAPTED TO BE ATTRACTED TO SAID MAGNETIC CORE MEANS IN THE PRESENCE OF UNIDIRECTIONAL FLUX FLOW THROUGH SAID AIR GAP. 